Sealing means are well known in the art. Examples of conventional seals include, for example, floating seals, compression rings, or spring loaded seals. Floating seals do not offer any type of centering during an assembly process. As a result, these seals often fall or sag radially until the inner diameter of the seal contacts the minor diameter of a seal gland, which can result in assembly issues or failure of the seal.
Compression seals do not offer a large degree of radial freedom between adjacent parts, and therefore can not be used to seal fully dynamic interfaces. Spring loaded seals do offer some degree of centering and radial compliance, but are costly to manufacture, and therefore not suitable for many applications.
Due to low cost of manufacture and good performance in fully dynamic interfaces, floating seals are a commonly preferred means of creating a sealed interface between two independently moveable components. However, because of the lack of the ability to self-center during assembly, these seals can often become damaged, torn, or broken during the assembly process. Specifically, a sizing tool may be used to compress the seal to a diameter smaller than the major diameter of the gland in which the seal is installed. However, when the tool is removed so that the seal can be installed between the two independently moveable components, the seal is no longer supported and can fall due to gravity so that the outer diameter of the seal drops below the major diameter of the gland, which may result in the seal being pinched when the two independently moveable components are engaged together.
Such a scenario is illustrated in FIG. 7, where floating seal 110 is being installed in groove 132 of hub 130 of a torque converter (not shown), to provide a sealed fully dynamic interface between the hub and piston plate 140. It should be appreciated that the hub and piston plate are shown for illustrative purposes only, and could be replaced by any two components which must be sealed, but which also must be independently moveable. By independently moveable we mean in any direction, including axially, radially, and rotatably.
For clarity, floating seal 110 is designated with reference numerals 110a and 110b to differentiate the top and bottom portions of the seal, but it should be understood that the seal is a single, integrated ring. Likewise, groove 132 is designated with reference numerals 132a and 132b to differentiate the top and bottom portions of the groove, but it should be understood that the groove is continuous about the periphery of the hub. Outer hub diameter or surface 134 and inner piston plate surface or diameter 144 are similarly designated with the identifiers “a” and “b” to differentiate their respective top and bottom portions, despite both being continuous surfaces about their respective components.
Piston plate 140 is generally a ring shaped plate which includes center bore 142 in which hub 130 is installed. When vertically orientated, as shown, floating seal 110 will fall or sag, so that the inner diameter of the seal rests at the base of groove top portion 132a, but so that a large gap is created, having a radial distance x2, between the base of groove bottom portion 132b and the inner diameter of the seal. As hub 130 is pressed into bore 142 of piston plate 140 in the direction of arrow 150, (or the piston plate in a direction opposite to the direction shown), surface bottom portions 134b and 144b of the hub and plate, respectively, will likely pinch or cut off a portion of the seal. The portion of the seal which is exposed to the inner diameter of the piston plate is the portion shown below the dashed line, which indicates the intended path of surface bottom diameter 144b of the piston plate. Alternatively stated, the radial falling of floating seal 110 results in a portion of the seal residing outside of bore 142, so that the seal will get pinched between the hub and piston plate when these two components are engaged. Surface top portions 134a and 144a of the hub and plate, however, will not damage seal top portion 110a, but will instead merely pass over, or slightly compress the ring into the groove, as desired.
After installation of the hub with the piston plate, visual inspection of seal 110 becomes impossible, since the seal is sandwiched between the two components. Thus, failure of the seal can only be determined by fully assembling and testing the torque converter, for example. In such a scenario, something as seemingly insignificant as a seal will become very costly and difficult to replace. Specifically, in the shown example of hub and piston plate of a torque converter, the torque converter must be largely disassembled and then reassembled. Some components are installed in the torque converter so that the components must be cut in order to complete disassembly. This not only ruins the cut components so that they need to be replaced with new parts, but creates shavings and debris from the cutting process, which requires the torque converter to be completely washed and cleaned to ensure no debris interferes with the performance of the torque converter. Only then, can the defective seal be replaced, and the hub, piston, and other components reassembled. A similar situation could occur in any assembly requiring a floating seal between two dynamic components.
Thus, there is a long-felt need for a floating seal which can center itself so that it is not likely to become damaged during assembly due to radial falling.